Groove and thread cutter.



'PATBNTED APR. 18, 1905.

F. B ERSZINSKY'. GROOVE AND THREAD CUTTER.

APPLIOATION FILED NOV. 3, 1903.

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UNITED STATES Patented April 18, 1905.

PATENT OFFICE.

FRIEDRICH BERSZINSKY, OF ESSEN, GERMANY, ASSIGNOR TO DE FRIES & CO.,AGTIEN-GESELLSCHAFT, OF DIISSELDORF, GERMANY.

GROOVE AND THREAD CUTTER.

SPECIFICATION forming part of Letters Patent No. 787,490, dated April18, 1905.

Application filed November 8, 1903. Serial No. 179,687-

To all whmn it may concern;

Be itknown that I, FRIEDRICH BERSZINSKY, a citizen of Germany, residingat Essen, Germany, haveinvented new and usefulImprovements in Groove andThread Cutters, of which the following is a specification.

This invention relates to an improved apparatus for cutting threads orgrooves and spirals for worm and gear wheels, ratchets, and

segments of threads for the breech of guns, &c. The apparatus is soconstructed that the cutter can be readily adjusted to the pitch desiredand that it is automatically lowered as the depth of the groove cut isto be increased.

In the accompanying drawings, Figure 1 is a front elevation, partly insection, of a lathe embodyingmyinvention; Fig. 2, a plan, partly insection, thereof; and Fig. 3, a cross-section on line A B, Fig. 1.

The letter a represents the cutter, which passes freely through acorresponding slot of a spindle c and is movable within a diametricalgroove Z formed in the head Z of a left sleeve section Z). This sleeveis slidably mounted upon the spindle 0 and participates in its rotationby means of a groove-and-feather connection. The cutter (Z is providedwith a laterally-projecting pin 0, that engages an eccentric groove (Zin the head a; of a second or right sleeve-section 5, also mounted onspindle 0. At a distance from head 1) the bore of sleeve Z) is enlargedto accommodate a spring g, embracing spindle 0. The right end of saidspindle terminates in a tenon 10, that engages a mortised shaft :13,which enters the bore of sleeve Z). By this construction spring g, whichbears with one end against shaftw, while its other end bears against aninner shoulder of sleeve 6', will push the latter against sleeve 6.Shaft 02, being supported by a bearing of the head-stock y, receivesrotary motion by toothed wheel 2/, and transmits the same throughspindle c and sleeve Z) to cutter 0. During the rotation of the sleevethe cutter receives an additional longitudinal movement, according tothe pitch of the thread to be out, in the following manner:

Into the bore of slide-rest q is fitted a hub .9, provided at its outerend with a bulged flange or cam Z. Slide-rest q is slitted, asat Q, sothat by tightening a pair of clampscrews g hub s is held in position.One side of cam 25 is engaged by a projection Z on flange k of sleeveZ), while its other side is' engaged by a roller m. This roller ispivoted within a housing w, attached to sleeve 6. When spindle crotates, sleeve 6 and cutter a will thus be reciprocated for a distancecorresponding to the bulge of cam 26. In this way the tool a is revolvedaround the spindle c and is reciprocated along the same to accord Withthe pitch of the thread desired. In order to gradually deepen the grooveat each revolution of the cutter, I provide sleeve Z) with aratchet-disk at, having teeth 0. The latter are engaged byapawl Z,pivoted at Z to aflange r of shaft :12. The pawl Z is provided with anarm Z, having spring w, that holds pawl Z in engagement with the ratcheta. If sleeve Z) moves to the right, Figs. 1 and 2, the ratchet n willapproach flange 1'. This movement causes pawl Z to turn on its pivotagainst the action of spring 10. During this motion pawl Z, engaging oneof the teeth 0, will take along ratchet 01, thus partially rotatingsleeve Z). This partial rotation of sleeve 6 causes'a slight advance ofthe tool (6 by means of eccentric groove (Z and pin 0. If the sleeve 6moves to the left, the distance between ratchet n and flange r willincrease and pawl Z will by spring u; be turned backward to engage a newtooth of ratchet n. In this way the tool is slightly advanced radiallyoutward at each rotation until the groove has the desired depth. Whenthe cutting of the groove has been completed, the machine is arrestedand the workholder is advanced to the proper position for cutting thenext groove. This being done, the cutter is set back to its initialposition by turning sleeve Z) by hand until the cutter is sufficientlyretracted and the machine thus set for cutting the next groove.

It Will be seen that the groove cut by my machine gradually increases indepth; but as the advance of the tool during each rotation is very smallthis increase may be practically ignored.

What I claim is- 1. In a groove-cutter, the combination of a rotatablespindle With a left sleeve rotatable with the spindle and having adiametric groove, means for reciprocating the sleeve, a reciprocableright sleeve having an eccentric groove, means for independentlyrotating the right sleeve upon the spindle, and a cutter positioned inthe diametric groove and having a part engaging the eccentric groove,substantially as specified.

2. In a groove-cutter, the combination of a rotatable spindle with aleft sleeve rotatable FRIEDRICH BERSZIN SKY.

WVitncsses:

HERMANN FRoBosE, PETER LIEBER.

